PLASMA TESTOSTERONE CONCENTRATION, BODY-WEIGHT, SOCIAL-DOMINANCE AND SCENT-MARKING IN MALE MARSUPIAL SUGAR GLIDERS (PETAURUS BREVICEPS MARSUPIALIA, PETAURIDAE)

Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live-trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body we ight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the h eaviest. In captivity this male is observed to be socially the most do minant and undertakes almost all of the scent-marking. At least three- quarters of each breeding season's births occur during the first month of the three- to four-month season (July-September/October), a passag e of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits o f high social status being immense.